Commit 3eb3d3e78 was a few bricks shy of a load: while it correctly
set the table's "interesting" flag when deciding to dump the data of
an extension config table, it was not correct to clear that flag
if we concluded we shouldn't dump the data. This led to the crash
reported in bug #16655, because in fact we'll traverse dumpTableSchema
anyway for all extension tables (to see if they have user-added
seclabels or RLS policies).
The right thing to do is to force "interesting" true in makeTableDataInfo,
and otherwise leave the flag alone. (Doing it there is more future-proof
in case additional calls are added, and it also avoids setting the flag
unnecessarily if that function decides the table is non-dumpable.)
This investigation also showed that while only the --inserts code path
had an obvious failure in the case considered by 3eb3d3e78, the COPY
code path also has a problem with not having loaded table subsidiary
data. That causes fmtCopyColumnList to silently return an empty string
instead of the correct column list. That accidentally mostly works,
which perhaps is why we didn't notice this before. It would only fail
if the restore column order is different from the dump column order,
which only happens in weird inheritance cases, so it's not surprising
nobody had hit the case with an extension config table. Nonetheless,
it's a bug, and it goes a long way back, not just to v12 where the
--inserts code path started to have a problem with this.
In hopes of catching such cases a bit sooner in future, add some
Asserts that "interesting" has been set in both dumpTableData and
dumpTableSchema. Adjust the test case added by 3eb3d3e78 so that it
checks the COPY rather than INSERT form of that bug, allowing it to
detect the longer-standing symptom.
Per bug #16655 from Cameron Daniel. Back-patch to all supported
branches.
Discussion: https://postgr.es/m/16655-5c92d6b3a9438137@postgresql.org
Discussion: https://postgr.es/m/18048b44-3414-b983-8c7c-9165b177900d@2ndQuadrant.com
pg_dump is oblivious to this kind of dependency, so they're lost on
dump/restores (and pg_upgrade). Have pg_dump emit ALTER lines so that
they're preserved. Add some pg_dump tests for the whole thing, also.
Reviewed-by: Tom Lane (offlist)
Reviewed-by: Ibrar Ahmed
Reviewed-by: Ahsan Hadi (who also reviewed commit 899a04f5ed61)
Discussion: https://postgr.es/m/20200217225333.GA30974@alvherre.pgsql
If the command is attempted for an extension that the object already
depends on, silently do nothing.
In particular, this means that if a database containing multiple such
entries is dumped, the restore will silently do the right thing and
record just the first one. (At least, in a world where pg_dump does
dump such entries -- which it doesn't currently, but it will.)
Backpatch to 9.6, where this kind of dependency was introduced.
Reviewed-by: Ibrar Ahmed, Tom Lane (offlist)
Discussion: https://postgr.es/m/20200217225333.GA30974@alvherre.pgsql
Renaming varchar_transform to varchar_support had a side effect
I hadn't foreseen: the core regression tests leave around a
transform object that relies on that function, so the name
change breaks cross-version upgrade tests, because the name
used in the older branches doesn't match.
Since the dependency on varchar_transform was chosen with the
aid of a dartboard anyway (it would surely not work as a
language transform support function), fix by just choosing
a different random builtin function with the right signature.
Also add some comments explaining why this isn't horribly unsafe.
I chose to make the same substitution in a couple of other
copied-and-pasted test cases, for consistency, though those
aren't directly contributing to the testing problem.
Per buildfarm. Back-patch, else it doesn't fix the problem.
Attempting to use a temporary table within a two-phase transaction is
forbidden for ages. However, there have been uncovered grounds for
a couple of other object types and commands which work on temporary
objects with two-phase commit. In short, trying to create, lock or drop
an object on a temporary schema should not be authorized within a
two-phase transaction, as it would cause its state to create
dependencies with other sessions, causing all sorts of side effects with
the existing session or other sessions spawned later on trying to use
the same temporary schema name.
Regression tests are added to cover all the grounds found, the original
report mentioned function creation, but monitoring closer there are many
other patterns with LOCK, DROP or CREATE EXTENSION which are involved.
One of the symptoms resulting in combining both is that the session
which used the temporary schema is not able to shut down completely,
waiting for being able to drop the temporary schema, something that it
cannot complete because of the two-phase transaction involved with
temporary objects. In this case the client is able to disconnect but
the session remains alive on the backend-side, potentially blocking
connection backend slots from being used. Other problems reported could
also involve server crashes.
This is back-patched down to v10, which is where 9b013dc has introduced
MyXactFlags, something that this patch relies on.
Reported-by: Alexey Bashtanov
Author: Michael Paquier
Reviewed-by: Masahiko Sawada
Discussion: https://postgr.es/m/5d910e2e-0db8-ec06-dd5f-baec420513c3@imap.cc
Backpatch-through: 10
Some makefiles were trying to do this:
temp-install: EXTRA_INSTALL=contrib/test_decoding
but that no longer works as of commit aa019da52: the macro is now
consulted by the checkprep target, one level down, and apparently
gmake doesn't propagate such macro settings recursively.
The problem is masked since 42e61c774 because pgxs.mk also sets up
EXTRA_INSTALL, and correctly applies it to the checkprep target.
Unfortunately I'd not risked back-patching that to before v11.
Since aa019da52 was pushed back to v10, it broke test_decoding
there (the only module for which this actually makes a difference
at present).
Hence, back-patch 42e61c774 to v10. Also, remove some demonstrably
useless settings of EXTRA_INSTALL in v10 and v11 (they'd already
been cleaned up in HEAD).
Per buildfarm.
Discussion: https://postgr.es/m/CAEepm=1pEJdwv6DSGmOfpX0EaX7L7sT28c1nXpqvQvmLfEWb1g@mail.gmail.com
This module overlooked this necessary fixup step on the results of
transformWhereClause(). It accidentally worked anyway, because the
constructed expression involved type "name" which is not collatable,
but it fell over while I was experimenting with changing "name" to
be collatable.
Back-patch, not because there's any live bug here in back branches,
but because somebody might use this code as a model for some real
application and then not understand why it doesn't work.
The "rb" prefix is used by Ruby, so that our existing code results
in name collisions that break plruby. We discussed ways to prevent
that by adjusting dynamic linker options, but it seems that at best
we'd move the pain to other cases. Renaming to avoid the collision
is the only portable fix anyway. Fortunately, our rbtree code is
not (yet?) widely used --- in core, there's only a single usage
in GIN --- so it seems likely that we can get away with a rename.
I chose to do this basically as s/rb/rbt/g, except for places where
there already was a "t" after "rb". The patch could have been made
smaller by only touching linker-visible symbols, but it would have
resulted in oddly inconsistent-looking code. Better to make it look
like "rbt" was the plan all along.
Back-patch to v10. The rbtree.c code exists back to 9.5, but
rb_iterate() which is the actual immediate source of pain was added
in v10, so it seems like changing the names before that would have
more risk than benefit.
Per report from Pavel Raiskup.
Discussion: https://postgr.es/m/4738198.8KVIIDhgEB@nb.usersys.redhat.com
Index DDL cascading on partitioned tables introduced a way for ALTER
TABLE to be called reentrantly. This caused an an important deficiency
in event trigger support to be exposed: on exiting the reentrant call,
the alter table state object was clobbered, causing a crash when the
outer alter table tries to finalize its processing. Fix the crash by
creating a stack of event trigger state objects. There are still ways
to cause things to misbehave (and probably other crashers) with more
elaborate tricks, but at least it now doesn't crash in the obvious
scenario.
Backpatch to 9.5, where DDL deparsing of event triggers was introduced.
Reported-by: Marco Slot
Authors: Michaël Paquier, Álvaro Herrera
Discussion: https://postgr.es/m/CANNhMLCpi+HQ7M36uPfGbJZEQLyTy7XvX=5EFkpR-b1bo0uJew@mail.gmail.com
The activation and deactivation of commit timestamp tracking has not
been handled consistently for a primary or standbys at recovery. The
facility can be activated at three different moments of recovery:
- The beginning, where a primary would use the GUC value for the
decision-making, and where a standby relies on the contents of the
control file.
- When replaying a XLOG_PARAMETER_CHANGE record at redo.
- The end, where both primary and standby rely on the GUC value.
Using the GUC value for a primary at the beginning of recovery causes
problems with commit timestamp access when doing crash recovery.
Particularly, when replaying transaction commits, it could be possible
that an attempt to read commit timestamps is done for a transaction
which committed at a moment when track_commit_timestamp was disabled.
A test case is added to reproduce the failure. The test works down to
v11 as it takes advantage of transaction commits within procedures.
Reported-by: Hailong Li
Author: Masahiko Sawasa, Michael Paquier
Reviewed-by: Kyotaro Horiguchi
Discussion: https://postgr.es/m/11224478-a782-203b-1f17-e4797b39bdf0@qunar.com
Backpatch-through: 9.5, where commit timestamps have been introduced.
The vertical tightness settings collapse vertical whitespace between
opening and closing brackets (parentheses, square brakets and braces).
This can make data structures in particular harder to read, and is not
very consistent with our style in non-Perl code. This patch restricts
that setting to parentheses only, and reformats all the perl code
accordingly. Not applying this to parentheses has some unfortunate
effects, so the consensus is to keep the setting for parentheses and not
for the others.
The diff for this patch does highlight some places where structures
should have trailing commas. They can be added manually, as there is no
automatic tool to do so.
Discussion: https://postgr.es/m/a2f2b87c-56be-c070-bfc0-36288b4b41c1@2ndQuadrant.com
Commit 372728b0d created some problems for usages like building a
subdirectory without having first done "make all" at the top level,
or for proceeding directly to "make install" without "make all".
The only reasonably clean way to fix this seems to be to force the
submake-generated-headers rule to fire in *any* "make all" or "make
install" command anywhere in the tree. To avoid lots of redundant work,
as well as parallel make jobs possibly clobbering each others' output, we
still need to be sure that the rule fires only once in a recursive build.
For that, adopt the same MAKELEVEL hack previously used for "temp-install".
But try to document it a bit better.
The submake-errcodes mechanism previously used in src/port/ and src/common/
is subsumed by this, so we can get rid of those special cases. It was
inadequate for src/common/ anyway after the aforesaid commit, and it always
risked parallel attempts to build errcodes.h.
Discussion: https://postgr.es/m/E1f5FAB-0006LU-MB@gemulon.postgresql.org
Everything of use to frontend code should now appear in the _d.h files,
and making this change frees us from needing to worry about whether the
catalog header files proper are frontend-safe.
Remove src/interfaces/ecpg/ecpglib/pg_type.h entirely, as the previous
commit reduced it to a confusingly-named wrapper around pg_type_d.h.
In passing, make test_rls_hooks.c follow project convention of including
our own files with #include "" not <>.
Discussion: https://postgr.es/m/23690.1523031777@sss.pgh.pa.us
This reworks how the tests to run are defined. Instead of having to
define all runs for all tests, we define those tests which should pass
(generally using one of the defined broad hashes), add in any which
should be specific for this test, and exclude any specific runs that
shouldn't pass for this test. This ends up removing some 4k+ lines
(more than half the file) but, more importantly, greatly simplifies the
way runs-to-be-tested are defined.
As discussed in the updated comments, for example, take the test which
does CREATE TABLE test_table. That CREATE TABLE should show up in all
'full' runs of pg_dump, except those cases where 'test_table' is
excluded, of course, and that's exactly how the test gets defined now
(modulo a few other related cases, like where we dump only that table,
or we dump the schema it's in, or we exclude the schema it's in):
like => {
%full_runs,
%dump_test_schema_runs,
only_dump_test_table => 1,
section_pre_data => 1, },
unlike => {
exclude_dump_test_schema => 1,
exclude_test_table => 1, }, },
Next, we no longer expect every run to be listed for every test. If a
run is listed in 'like' (directly or through a hash) then it's a 'like',
unless it's listed in 'unlike' in which case it's an 'unlike'. If it
isn't listed in either, then it's considered an 'unlike' automatically.
Lastly, this changes the code to no longer use like/unlike but rather to
use 'ok()' with 'diag()' which allows much more control over what gets
spit out to the screen. Gone are the days of the entire dump being sent
to the console, now you'll just get a couple of lines for each failing
test which say the test that failed and the run that it failed on.
This covers both the pg_dump TAP tests in src/bin/pg_dump and those in
src/test/modules/test_pg_dump.
Make buffer 1 byte larger to fit a sign. It's actually impossible for
there to be a sign in practice, but this is still required to keep GCC 7
happy.
Cleanup from commit 51bc271790eb234a1ba4d14d3e6530f70de92ab5.
Based on a suggestion from Peter Eisentraut.
Author: Peter Geoghegan
Reported-By: Peter Eisentraut
Discussion: https://postgr.es/m/d1cc82ed-d07d-cef2-7c00-2e987f121648@2ndquadrant.com
A Bloom filter is a space-efficient, probabilistic data structure that
can be used to test set membership. Callers will sometimes incur false
positives, but never false negatives. The rate of false positives is a
function of the total number of elements and the amount of memory
available for the Bloom filter.
Two classic applications of Bloom filters are cache filtering, and data
synchronization testing. Any user of Bloom filters must accept the
possibility of false positives as a cost worth paying for the benefit in
space efficiency.
This commit adds a test harness extension module, test_bloomfilter. It
can be used to get a sense of how the Bloom filter implementation
performs under varying conditions.
This is infrastructure for the upcoming "heapallindexed" amcheck patch,
which verifies the consistency of a heap relation against one of its
indexes.
Author: Peter Geoghegan
Reviewed-By: Andrey Borodin, Michael Paquier, Thomas Munro, Andres Freund
Discussion: https://postgr.es/m/CAH2-Wzm5VmG7cu1N-H=nnS57wZThoSDQU+F5dewx3o84M+jY=g@mail.gmail.com
Currently, if operator_predicate_proof() is given an operator clause like
"something op NULL", it just throws up its hands and reports it can't prove
anything. But we can often do better than that, if the operator is strict,
because then we know that the clause returns NULL overall. Depending on
whether we're trying to prove or refute something, and whether we need
weak or strong semantics for NULL, this may be enough to prove the
implication, especially when we rely on the standard rule that "false
implies anything". In particular, this lets us do something useful with
questions like "does X IN (1,3,5,NULL) imply X <= 5?" The null entry
in the IN list can effectively be ignored for this purpose, but the
proof rules were not previously smart enough to deduce that.
This patch is by me, but it owes something to previous work by
Amit Langote to try to solve problems of the form mentioned.
Thanks also to Emre Hasegeli and Ashutosh Bapat for review.
Discussion: https://postgr.es/m/3bad48fc-f257-c445-feeb-8a2b2fb622ba@lab.ntt.co.jp
One of the things canonicalize_qual() does is to remove constant-NULL
subexpressions of top-level AND/OR clauses. It does that on the assumption
that what it's given is a top-level WHERE clause, so that NULL can be
treated like FALSE. Although this is documented down inside a subroutine
of canonicalize_qual(), it wasn't mentioned in the documentation of that
function itself, and some callers hadn't gotten that memo.
Notably, commit d007a9505 caused get_relation_constraints() to apply
canonicalize_qual() to CHECK constraints. That allowed constraint
exclusion to misoptimize situations in which a CHECK constraint had a
provably-NULL subclause, as seen in the regression test case added here,
in which a child table that should be scanned is not. (Although this
thinko is ancient, the test case doesn't fail before 9.2, for reasons
I've not bothered to track down in detail. There may be related cases
that do fail before that.)
More recently, commit f0e44751d added an independent bug by applying
canonicalize_qual() to index expressions, which is even sillier since
those might not even be boolean. If they are, though, I think this
could lead to making incorrect index entries for affected index
expressions in v10. I haven't attempted to prove that though.
To fix, add an "is_check" parameter to canonicalize_qual() to specify
whether it should assume WHERE or CHECK semantics, and make it perform
NULL-elimination accordingly. Adjust the callers to apply the right
semantics, or remove the call entirely in cases where it's not known
that the expression has one or the other semantics. I also removed
the call in some cases involving partition expressions, where it should
be a no-op because such expressions should be canonical already ...
and was a no-op, independently of whether it could in principle have
done something, because it was being handed the qual in implicit-AND
format which isn't what it expects. In HEAD, add an Assert to catch
that type of mistake in future.
This represents an API break for external callers of canonicalize_qual().
While that's intentional in HEAD to make such callers think about which
case applies to them, it seems like something we probably wouldn't be
thanked for in released branches. Hence, in released branches, the
extra parameter is added to a new function canonicalize_qual_ext(),
and canonicalize_qual() is a wrapper that retains its old behavior.
Patch by me with suggestions from Dean Rasheed. Back-patch to all
supported branches.
Discussion: https://postgr.es/m/24475.1520635069@sss.pgh.pa.us
Commit b08df9cab left things rather poorly documented as far as the
exact semantics of "clause_is_check" mode went. Also, that mode did
not really work correctly for predicate_refuted_by; although given the
lack of specification as to what it should do, as well as the lack
of any actual use-case, that's perhaps not surprising.
Rename "clause_is_check" to "weak" proof mode, and provide specifications
for what it should do. I defined weak refutation as meaning "truth of A
implies non-truth of B", which makes it possible to use the mode in the
part of relation_excluded_by_constraints that checks for mutually
contradictory WHERE clauses. Fix up several places that did things wrong
for that definition. (As far as I can see, these errors would only lead
to failure-to-prove, not incorrect claims of proof, making them not
serious bugs even aside from the fact that v10 contains no use of this
mode. So there seems no need for back-patching.)
In addition, teach predicate_refuted_by_recurse that it can use
predicate_implied_by_recurse after all when processing a strong NOT-clause,
so long as it asks for the correct proof strength. This is an optimization
that could have been included in commit b08df9cab, but wasn't.
Also, simplify and generalize the logic that checks for whether nullness of
the argument of IS [NOT] NULL would force overall nullness of the predicate
or clause. (This results in a change in the partition_prune test's output,
as it is now able to prune an all-nulls partition that it did not recognize
before.)
In passing, in PartConstraintImpliedByRelConstraint, remove bogus
conversion of the constraint list to explicit-AND form and then right back
again; that accomplished nothing except forcing a useless extra level of
recursion inside predicate_implied_by.
Discussion: https://postgr.es/m/5983.1520487191@sss.pgh.pa.us
I'd initially supposed that predicate_refuted_by(..., true) ought to
say that "A refutes B" means "non-falsity of A implies non-truth of B".
But it seems better to define it as "truth of A implies non-truth of B".
This is more useful in the current system, slightly easier to prove,
and in closer correspondence to the existing code behavior.
With this change, test_predtest no longer claims that any existing
test cases show false proof reports, though there still are cases
where we could prove something and fail to.
Discussion: https://postgr.es/m/5983.1520487191@sss.pgh.pa.us
The predicate-proof code in predtest.c is a bit hard to test as-is:
you have to construct a query whose plan changes depending on the success
of a test, and in tests that have been around for awhile, it's always
possible that the plan shape is now being determined by some other factor.
Our existing regression tests aren't doing real well at providing full
code coverage of predtest.c, either. So, let's add a small test module
that allows directly inspecting the results of predicate_implied_by()
and predicate_refuted_by() for arbitrary boolean expressions.
I chose the set of tests committed here in order to get reasonably
complete code coverage of predtest.c just from running this test
module, and to cover some cases called out as being interesting in
the existing comments. We might want to add more later. But this
set already shows a few cases where perhaps things could be improved.
Indeed, this exercise proves that predicate_refuted_by() is buggy for
the case of clause_is_check = true, though fortunately we aren't using
that case anywhere yet. I'll look into doing something about that in
a separate commit. For now, just memorialize the current behavior.
Discussion: https://postgr.es/m/5983.1520487191@sss.pgh.pa.us
Historically, pg_dump has "set search_path = foo, pg_catalog" when
dumping an object in schema "foo", and has also caused that setting
to be used while restoring the object. This is problematic because
functions and operators in schema "foo" could capture references meant
to refer to pg_catalog entries, both in the queries issued by pg_dump
and those issued during the subsequent restore run. That could
result in dump/restore misbehavior, or in privilege escalation if a
nefarious user installs trojan-horse functions or operators.
This patch changes pg_dump so that it does not change the search_path
dynamically. The emitted restore script sets the search_path to what
was used at dump time, and then leaves it alone thereafter. Created
objects are placed in the correct schema, regardless of the active
search_path, by dint of schema-qualifying their names in the CREATE
commands, as well as in subsequent ALTER and ALTER-like commands.
Since this change requires a change in the behavior of pg_restore
when processing an archive file made according to this new convention,
bump the archive file version number; old versions of pg_restore will
therefore refuse to process files made with new versions of pg_dump.
Security: CVE-2018-1058
AclObjectKind was basically just another enumeration for object types,
and we already have a preferred one for that. It's only used in
aclcheck_error. By using ObjectType instead, we can also give some more
precise error messages, for example "index" instead of "relation".
Reviewed-by: Michael Paquier <michael.paquier@gmail.com>
It's become apparent during testing that there are problems with at
least the testing regime. I don't think we should have it without a
working test regime, and the difficulties might indicate implementation
problems anyway, so I'm backing out the whole thing until that's sorted
out.
This reverts commits 7459484 9989f92 cd8ce3a
The module requires a preloaded library and the defect can't be cured by
a LOAD instruction in the test script. To achieve this we override the
installcheck target in the module's Makefile, and exclude ithe module in
vcregress.pl.
Along the way, revert commit 9989f92aabd.
Makefile.global assigns this prerequisite to every target named "check",
but similar targets must mention it explicitly. Affected targets
failed, tested $PATH binaries, or tested a stale temporary installation.
The src/test/modules examples worked properly when called as "make -C
src/test/modules/$FOO check", but "make -j" allowed the test to start
before the temporary installation was in place. Back-patch to 9.5,
where commit dcae5faccab64776376d354decda0017c648bb53 introduced the
shared temp-install.
I noticed the tmp_check subdirectory wasn't getting cleaned up
after a check-world run. Apparently pgxs.mk will only do this
for you if you've defined REGRESS. The only other src/test/modules
Makefile that does not set that is snapshot_too_old, and it
does it like this.
Add bgw_type field to background worker structure. It is intended to be
set to the same value for all workers of the same type, so they can be
grouped in pg_stat_activity, for example.
The backend_type column in pg_stat_activity now shows bgw_type for a
background worker. The ps listing also no longer calls out that a
process is a background worker but just show the bgw_type. That way,
being a background worker is more of an implementation detail now that
is not shown to the user. However, most log messages still refer to
'background worker "%s"'; otherwise constructing sensible and
translatable log messages would become tricky.
Reviewed-by: Michael Paquier <michael.paquier@gmail.com>
Reviewed-by: Daniel Gustafsson <daniel@yesql.se>
This improves the regression tests' coverage of rbtree.c from pretty
awful (because some of the functions aren't used yet) to basically 100%.
Victor Drobny, reviewed by Aleksander Alekseev and myself
Discussion: https://postgr.es/m/c9d61310e16e75f8acaf6cb1c48b7b77@postgrespro.ru
Several callers of PostgresNode::poll_query_until() neglected to check
for failure; I do not think that's optional. Also, rewrite one place
that had reinvented poll_query_until() for no very good reason.
Don't move parenthesized lines to the left, even if that means they
flow past the right margin.
By default, BSD indent lines up statement continuation lines that are
within parentheses so that they start just to the right of the preceding
left parenthesis. However, traditionally, if that resulted in the
continuation line extending to the right of the desired right margin,
then indent would push it left just far enough to not overrun the margin,
if it could do so without making the continuation line start to the left of
the current statement indent. That makes for a weird mix of indentations
unless one has been completely rigid about never violating the 80-column
limit.
This behavior has been pretty universally panned by Postgres developers.
Hence, disable it with indent's new -lpl switch, so that parenthesized
lines are always lined up with the preceding left paren.
This patch is much less interesting than the first round of indent
changes, but also bulkier, so I thought it best to separate the effects.
Discussion: https://postgr.es/m/E1dAmxK-0006EE-1r@gemulon.postgresql.org
Discussion: https://postgr.es/m/30527.1495162840@sss.pgh.pa.us
The new indent version includes numerous fixes thanks to Piotr Stefaniak.
The main changes visible in this commit are:
* Nicer formatting of function-pointer declarations.
* No longer unexpectedly removes spaces in expressions using casts,
sizeof, or offsetof.
* No longer wants to add a space in "struct structname *varname", as
well as some similar cases for const- or volatile-qualified pointers.
* Declarations using PG_USED_FOR_ASSERTS_ONLY are formatted more nicely.
* Fixes bug where comments following declarations were sometimes placed
with no space separating them from the code.
* Fixes some odd decisions for comments following case labels.
* Fixes some cases where comments following code were indented to less
than the expected column 33.
On the less good side, it now tends to put more whitespace around typedef
names that are not listed in typedefs.list. This might encourage us to
put more effort into typedef name collection; it's not really a bug in
indent itself.
There are more changes coming after this round, having to do with comment
indentation and alignment of lines appearing within parentheses. I wanted
to limit the size of the diffs to something that could be reviewed without
one's eyes completely glazing over, so it seemed better to split up the
changes as much as practical.
Discussion: https://postgr.es/m/E1dAmxK-0006EE-1r@gemulon.postgresql.org
Discussion: https://postgr.es/m/30527.1495162840@sss.pgh.pa.us
